Exhaust system for internal combustion engines

Abstract

An exhaust system for internal combustion engines, in particular two-cycle internal combustion engines, includes a resonance-type exhaust part having at least one diffuser-cone unit formed with a diffuser, a countercone, and a connecting part with a preferably constant cross section extending between the diffuser outlet cross section and cone inlet cross section. In order to provide the resonance-type exhaust part as compact as possible by employing a simple production method, the connecting part is formed as a first deflection arc, preferably with an angle of deflection of about 180°±30°.

What is claimed is:  
     
       1. An exhaust system for an internal combustion engine with a resonance-type exhaust part, comprising: 
       at least one diffuser-cone unit with a diffuser, a countercone, and a connecting part for providing a first deflection arc between a diffuser outlet cross section and countercone inlet cross section;  
       means forming a second deflection arc in an initial zone of the diffuser; and  
       means forming a third deflection arc in an end zone of the countercone,  
       a central line of the second deflection arc being arranged substantially in a second plane which is inclined to a first plane defined by  
       a central line of the first deflection arc, with the second plane being arranged approximately normal to the first plane, and  
       a third deflection arc being arranged in a third plane which is inclined to the first plane, with the third plane enclosing an angle of approximately 90° to the first plane and being arranged approximately parallel to the second plane.  
     
     
       2. The exhaust system according to claim  1 , wherein the first deflection arc has an angle of deflection of approximately 180° ± 30°. 
     
     
       3. The exhaust system according to claim  1 , wherein the second deflection arc has an angle of deflection of 180° ± 30°. 
     
     
       4. The exhaust system according to claim  1 , wherein the third deflection arc has a deflection angle of 180° ± 30°. 
     
     
       5. The exhaust system according to claim  1 , wherein a flow path through the resonance-type exhaust part is arranged with at least four passes, with a first and fourth pass being formed by an inlet part and an end part, and a second pass comprising the diffuser and a third pass the countercone. 
     
     
       6. The exhaust system according to claim  1 , wherein the diffuser is formed by a diffuser insert. 
     
     
       7. The exhaust system according to claim  6 , wherein also the inlet part is formed by the diffuser insert. 
     
     
       8. The exhaust system according to claim  6 , wherein the second deflection arc is formed by the diffuser insert. 
     
     
       9. The exhaust system according to claim  6 , wherein at least partly the first deflection arc is formed by the diffuser insert. 
     
     
       10. The exhaust system according to claim  6 , wherein the diffuser insert is arranged as a deep-drawing part. 
     
     
       11. The exhaust system according to claim  1 , wherein the countercone is formed by a cone insert. 
     
     
       12. The exhaust system according to claim  11 , wherein also the end part is formed by the cone insert. 
     
     
       13. The exhaust system according to claim  11 , wherein also the third deflection arc is formed by the cone insert. 
     
     
       14. The exhaust system according to claim  11 , wherein also at least partly the first deflection arc is formed by the cone insert. 
     
     
       15. The exhaust system according to claim  11 , wherein the cone insert is arranged as a deep-drawing part. 
     
     
       16. The exhaust system according to claim  1 , wherein the diffuser insert and the cone insert are mutually connected, with a separating plate being arranged between the diffuser insert and the cone insert. 
     
     
       17. The exhaust system according to claim  1 , wherein baffle plates are arranged in the zone of the first, second and third deflection arcs, with the baffle plates being fastened to the separating plate. 
     
     
       18. The exhaust system according to claim  1 , wherein the diffuser is arranged as a double diffuser, with at least one secondary diffuser with the same inlet/outlet cross-sectional ratio as the diffuser, being arranged within the diffuser, with the secondary diffuser being fastened to the separating plate. 
     
     
       19. The exhaust system according to claim  1 , wherein the resonance-type exhaust part is provided with at least two diffuser cone units which are switched in parallel in respect of flow and are arranged symmetrically with respect to a central plane and branch off from a common inlet piece and open into a common end piece, with the branches and the opening being arranged in the zone of a central plane. 
     
     
       20. The exhaust system according to claim  1 , wherein at least one part selected from the group separating plate, diffuser insert, cone insert, baffle plates and secondary diffuser is catalytically coated. 
     
     
       21. The exhaust system according to claim  1 , wherein the resonance-type exhaust part consists, at least in sections, of ceramics. 
     
     
       22. A resonance-type exhaust apparatus for an internal combustion engine which comprises: 
       a diffuser-countercone unit which includes a diffuser member that conveys exhaust gas therethrough, a countercone member that conveys exhaust gas therethrough, and a curved first connection part that deflects exhaust gas in a first arc from an outlet of said diffuser to an inlet of said countercone part,  
       an inlet member which conveys exhaust gas therethrough,  
       a second connection part which deflects exhaust gas in a second arc from an outlet of said inlet member to an inlet of said diffuser member,  
       an end piece which conveys exhaust gas therethrough, and  
       a third connection part which deflects exhaust gas in a third arc from an outlet of said countercone member to an inlet of said end piece,  
       a central line of the third arc defining a plane which is approximately parallel with a plane defined by a central line of the second arc and approximately perpendicular to a plane defined by a central line of the first arc.